Find the general solution. a. y^ prime +sec x y=cos x . b. y^ prime +y= 1 2 (e^ x -e^ -x ) . c. y^ prime + y x = 1 x^ 4 y^ -3/4 d. y^ prime = y x+y

Charlie is at an amusement park that has 18 different rides. each ride costs $1.75. the function c(r) = 1.75r represents the total amount of money that charlie will spend if he goes on r rides, but he never goes on the same one more than once. what domain and range are reasonable for the function?